Continuing:
Rehnquist (sp?) is the most likely justice to leave the court in the near future. He's conservative. If he is not replaced, that leaves the court likely to have a 4-4 split. Since 4-4 splits leave the lower court's decision intact, you could get a frenzy of forum shopping by special interests bring test cases. Consider, for example, that decisions from the 9th Circuit would not get reversed in such a scenario. How much damage would the opposing side take if they simply refused to confirm someone that they might be able to paint as too extreme?
If cloture can be broken, that would be something else. But otherwise, conservatives might be faced with the choice of either compromise or disaster.
Except for sitting to actually hear cases if prohibited for health reasons, according to analysis I have read and heard discussed, Rehnquist can still vote from anywhere (which includes home, a hospital bed etc).
If there should come a time where his mental faculties prohibited his participation, then there would be a 4-4 split. But until that time, a split is not possible.